Improvement in steam-boilers



C. J. GALLOWAY 8:. C. H. HOLT.

STEAM-BOILERS.

Patented Aug.8, 1876.

N P5151; IIHITO'UTNOWHER, WASHINGTON. D C.

UNITED STATES PATENT OEEIoE.

CHARLES J. GALLOWAY AND CHARLES H. HOLT, OF MANCHESTER, ENGLAND.

IMPROVEMENT IN STEAM-BOILERS.

Specification forming part of Letters Patent No. 180.863, dated August8, 1876; application filed February 8, 1876.

To all whom it may concern:

Be it known that we, CHARLES JOHN GAL- LOWAY, of Knott Mill Iron Works,Manchester, in the county of Lancaster, England, engineer, and CHARLESHERBERT HOLT, of Manchester aforesaid, engineer, have invented anImprovement in Steam-Boilers; and do hereby declare that the followingdescription, taken in connection with the accompanying sheet ofdrawings, hereinafter referred to, forms a full and exact specificationof the same, wherein we have set forth the nature and principles of oursaid improvements, by which our invention may be distinguished fromothers of a similar class, together with such parts as we claim anddesire to secure by Letters Patent-that is to say This invention relatesto internal-fined or Cornish steam-boilers having water-tubes fixedtransverselyinside the internal flues. In such boilers it is usualtoconstruct the flues of an elliptic form in transverse section, and tofix the tubes'therein in a vertical or parallel position. By thisarrangement the water-tubes necessarily vary in length and configurationas regards the flanged ends, when flanged tubes are employed, accordingto the position they occupy in the elliptic flue, and consequently thecost of manufacture of such boilers is rendered much greater than wouldbe the case if the tubes could all be made identical in form, so thatthey could be manufactured on a large scale, and consequently at acomparatively cheap rate, by special machinery. Now, according to ourpresentinvention, we attain this object by constructing the internalflue of the boiler with its upper and lower sides curved to a centerexternal to the flue, and by fixing therein water-tubes radiating fromthe same or nearly the same center from which the curved sides arestruck.

The accompanying drawings shows a transverse section of a steam-boilerconstructed according to this invention-namely, with the concave upperside A and the convex lower side A both struck from one and the samecenter, B, and with transverse watertubes C C, all radiating from thesame or nearly the same center, B, from which the curved sides arestruck. Thus it will be seen that all the tubes C will be identical inform, and interchangeable, the top and bottom flanges c 0 being allsquare to the center line of the tube, so that, in addition to theadvantage above mentioned of being able to manufacture them on a largescale, the labor and care required in fitting the tubes in their placesin the flue will be greatly reduced, resulting in a still greatercheapening of the cost of manufacture; also, in the case of conical orGalloway tubes, such as are shown in the drawing, the further advantageis gained that, as the flanges of the lower ends of the tubes can bebrought as close together as those of the upper ends, the bottom platesof the flues need not be made of increased strength, as was necessarywith the vertical arrangement of conical tubes used heretofore, onaccount of the extent of unsupported plate that necessarily occurredbetween the flanges of the lower small ends when those of the upper endswere close together.

Although this improved system of construction offers special advantagesin the case of flanged tubes, whether of conical or cylindrical shape,yet it may also be employed with advantage where tubes of small diameterwithout flanges, such as locomotive-tubes, are employed, the tubes beingfixed in the plates of the flue in any well-known manner, as in thiscase the advantage of having the tubes all identical as regards theirlength, and consequently interchangeable, would still be attained.

Having thus described the nature of our invention, and the best means weknow of carrying it out in practice, we claim- An internal-fined orCornish boiler, having the upper and lower sides of its flue curved toone and the same center, external to the flue, in combination withtransverse watertubes radiating from the same center from which thecurved upper and lower sides are struck.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses this 5th day of November,1876.

CHARLES JOHN GALLOWAY. CHARLES HERBERT HOLT.

Witnesses:

JOHN BROWN PAYNE, HENRY GALLOWAY.

